1. Field of the Invention
The present invention relates generally to plasma deposition and etch tools, and more particularly to electrostatic sticking of a processed substrate to the substrate stage of such plasma deposition/etch tools.
2. Description of the Prior Art
Magnetic heads for hard disk drives are fabricated in large numbers upon the surface of wafer substrates, and many fabrication steps, utilizing a variety of processing equipment, are involved. Some of the typical processing steps involve the use of plasma deposition tools or plasma etching tools to deposit or remove layers of material from the wafer surface. Such tools include enclosed chambers, typically with reduced atmospheric pressure and high RF voltages, in which the substrate is placed and in which the plasmas are created to interact with the exposed surface of the substrate. It is a common occurrence that unwanted electrostatic charge can build up on the wafer substrate, causing it to electrostatically cling to the wafer mounting mechanism within the chamber. The occurrence of wafer sticking can become a serious problem because it disrupts the automated processing of wafers within the wafer processing equipment. Typically, the equipment must be shut down to allow mechanical intervention to free the stuck wafer. This results in unwanted processing delays in the use of the automated wafer processing equipment and may cause damage to the wafer.